[High-quality materials] The chuck of the engraving and cutting machine is made of carbon steel materials, which has good flexibility and wear resistance.[Hole diameter] 6mm/6.35mm/8mm, 3 sizes meet different usage needs. Also supplied with 2 nuts.[Woodworking Tools] The router clamp is suitable for engraving wood milling, automobiles, molds and mechanical engineering. Is the perfect woodworking tool for engraving machine, wood router.[Easy to carry] The cutter chuck is easy to carry, has very precise, tight and stable clamping, and improves work efficiency.[Easy to use] Fine workmanship, stable performance, very easy to use.Features:Hole diameter: 6/6.35/8mm.Quantity: 6pcs (2pcs for each size) +2pcs nutsMaterial: carbon steel.Height: 3 pieces 20 mm, 2 pieces 8.4 mm, 1 piece 7 mmHigh resistance and hardness.Easy to use.Sustainable use.The package includes:2pcs*6mm Clamp adapter.2pcs * 6.35mm Clamp Adapter.2pcs*8mm Clamp Adapter.2pcs*nuts2-3cm difference exists due to different measurement way, please confirm the detailed size before ordering, thanks for your understanding & cooperation.According to the different monitors and light, please allow a slight color difference.